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Side Effects and Complications of Seed Implants

 

This CAT scan obtained after a seed implant shows the distribution of the seeds in the prostate gland (red circle) and away from the rectum.  Ideally the seeds will be evenly distributed through the gland (except in the center near the urethra) but sometimes they float or bunch up and are not as evenly distributed. This can lead to hot spots (a higher dose than desired) or cool spots (a lower dose than desired.)



* summary side effects
* bladder irritation (dysuria)
* bladder obstruction
* rectal problems
* impotence
* incontinence

 

Short term: most of the patients go home the same day and have mild bladder burning and blood in the urine which usually clears by the next day. Some men have pain in their perineum and benefit from an ice bag. Some men get swelling and obstruction problems (getting the bladder to empty.) Most of the men are sent home with Medrol-Dose-Pak (a steroid to prevent swelling) and Flomax wich can cause dizziness. (Drugs to treat obstruction are as noted: Alpha Reductase Inhibitors: Proscar (finasteride) and Avodart (dutasteride) interfere with the production of a hormone involved with BPH. This can help make the prostate smaller and improve symptoms. Alpha Blockers: Hytrin (terazosin), Cardura (doxazosin), Flomax (tamsulosin) and Uroxatrol(Alfuzosin) all help relax the smooth muscle of the prostate and bladder neck. This helps improve urine flow and reduce the blockage of the bladder.)

 

 

 

 

From the NCI: "Interstitial implantation of radioisotopes done through a transperineal technique with either ultrasound or CT guidance is being done in carefully selected patients with T1 or T2A tumors. Short term results in these patients are similar to those for radical prostatectomy or external-beam radiation therapy. One advantage is that the implant is performed as outpatient surgery. The rate of maintenance of sexual potency with interstitial implants has been reported to be 86% to 92%, which compares with rates of 10% to 40% with radical prostatectomy and 40% to 60% with external-beam radiation therapy. However, urinary tract frequency, urgency, and less commonly, urinary retention are seen in most patients but subside with time. Rectal ulceration may also be seen. In 1 series, a 10% 2-year actuarial genitourinary grade 2 complication rate and a 12% risk of rectal ulceration was seen. This risk decreased with increased operator experience and modification of implant technique.

Short Term Side Effects
  Immediately after the implant and when the catheter is removed, some men have burning or pressure during urination due to swelling of the gland from the needle punctures. This lasts only a few days. There may also be soreness and bruising behind the scrotal area where the needles were inserted. After a period of two or three weeks further irritation of the gland develops from the radioactivity and the patient may notice burning on urination, pressure,  frequency and some slight rectal irritation or diarrhea. The radioactive half life of the seeds (Iodine-125 60 days and Palladium-103 for 17days) measures how long it takes until half the radioactivity wears off. So after 4 half lives (8 months for iodine and 2 months for palladium) the seeds should only have 1/16 or 6% of their radioactivity left (1/2 X 1/2 X 1/2 X 1/2) There is a small risk of acute obstruction (requiring continued use of the Foley catheter) after the implant, particularly if the gland was large or the patient had some obstructive problems (slow urination) already. We generally use Decadron at the time of the implant and Flomax afterwards to lower the risk

Long Term Side Effects
 The risk of  urinary problems (frequency or incontinence) is very small, as is the risk of rectal problems. (The risk of a rectal ulcer resulting in a fistula is probably less than 1%, and can be caused by a rectal biopsy after a seed implant.)   The risk of impotence is related to age and is higher if the patient also receives external beam irradiation or hormones.A recent review of complications was as noted (Sem Rad Onc 1993;3:240):

There are other uncertain risks (e.g. migration of the seeds into the bloodstream and into the lung:) Implications of radioactive seed migration to the lungs after prostate brachytherapy. Ankem     Urology 2002 Apr;59(4):555-9

To review the incidence and the impact of pulmonary seed migration after prostate brachytherapy on lung function. Isolated reports of seed migration to the lungs after prostate brachytherapy have been published; however, the clinical consequences of this pulmonary migration have not been adequately evaluated. A total of 83 patients underwent prostate brachytherapy during the study period and 58 patients underwent chest radiography. Seed migration occurred in 21 (36.2%) of 58 patients. Thirty-four (0.71%) of 4755 seeds used migrated to the lungs. Clinical and pulmonary function testing revealed no consistent abnormality attributable to seed migration.

 

Sample Patient Consent Form RTOG 98-05
RISKS AND DISCOMFORTS

Cancer treatments often have side effects. The treatment used in this program may cause all, some, or none of the side effects listed. In addition, there is always the risk of very uncommon or previously unknown side effects occurring.

Implant: The possibility exists for infection but this should be controlled with antibiotics should infection occur. There will be soreness in the implant area. The implant itself has the possible side effects of temporary fatigue, diarrhea, abdominal cramps, bladder irritation with some bleeding, incontinence and, in some patients, inability to have an erection. There is also a chance of permanent injury to the bladder, urethra, bowel, and other tissues in the pelvis. The side effects related to the bladder,urethra, and bowel may take some months to years to occur. Another small risk is the movement of a radioactive seed to the lungs. Very small  amounts of radiation can reach other people. I should follow the special precautions from my doctor if I'm around small children  and pregnant women.

Transrectal ultrasound: Other than discomfort, there really is not a great risk from the transrectal ultrasound.

CT scan with contrast: An allergic reaction due to the contrast dye could occur but, otherwise, this doesn't carry any serious risk.

Anesthesia: There is the possibility of blood pressure problems, heart rhythm problems, breathing changes, drug reactions, nausea, vomiting, headache, sore throat, heart attack, stroke, or death.

Other: There may be some unknown or unanticipated discomforts or risks in addition to those specified above, as this irradiation technique, although not new, is somewhat different from techniques with permanent implantation in the past. Every precaution will be taken to assure my safety to minimize any discomfort that I may experience.
 

Health-related quality of life in men receiving prostate brachytherapy on RTOG 98-05

Feigenberg, IJROBP 2005;62:956

Purpose: To prospectively assess health-related quality of life (HRQOL) during the first year after treatment with prostate brachytherapy (PB) alone for T1c-2a prostate cancer.

Materials and Methods: Ninety-eight patients from 24 institutions were eligible and properly entered on this study. All patients were treated with PB alone using I-125 (Oncura Model 6711). The prescription dose was 145 Gy. Three separate health-related quality of life questionnaires (HRQOL) (Functional Assessment of Cancer Therapy-Prostate [FACT-P], Sexual Adjustment Questionnaire [SAQ], and International Prostate Symptom Score [IPSS]) were self-administered before and after PB (baseline; 3, 6, 9, and 12 months after PB). The standard error of the mean (SEM) was used to analyze changes in HRQOL scores over time. Patients who improved greater than the SEM were categorized as improved; patients that declined greater than the SEM were categorized as declined; patients were otherwise categorized as stable. All changes are measured using the pretreatment HRQOL score as baseline.

Results: The percentage of men who reported the ability to have an erection decreased from 73% at baseline (65% unassisted, 8% assisted) to 57% at 1 year (36% unassisted, 21% assisted). The rate of urinary incontinence increased to 14% at 6 months but had decreased to 1% at the 12-month follow-up. At 1 year after PB, 80% of men reported decreased sexual functioning according to SAQ scores. More than 60% of men reported decreased urinary function at 12 months compared with baseline.

Conclusions: This article represents the first prospective, multi-institutional study of HRQOL in men treated with PB and demonstrates that patients undergoing PB have a very high overall HRQOL. The rate of incontinence by 1 year after PB is low, but many patients continue to have obstructive symptoms at 1 year. Although 78% of 1-year respondents state that they can achieve an erection with or without assistance, almost 50% report a decrease in sexual function.